A conventional pharmaceutical injection device of this type comprised a main case, a cartridge holder provided openably and closeably to this main case, a piston that is provided inside this main case so as to be able to protrude from a pharmaceutical cartridge held in the cartridge holder, a piston drive mechanism that can make this piston protrude from the pharmaceutical cartridge, and a controller that is connected to this drive mechanism (see Patent Literature 1 below, for example).
Patent Literature 1: Japanese Laid-Open Patent Application 2012-50847